Galvanized iron (GI) sheets are basically steel sheets which have been coated with zinc. These sheets include a range of hot dip galvanized and electro-galvanized steel sheet. The zinc coating provides a continuous barrier which does not allow moisture and oxygen to reach the steel.The G.I. Sheet is a metal sheet coated with protective metallic and organic coatings that prevents rust. This is commonly used in automotive, wind, and solar industries. While the B.I. Sheet is made up of copper and aluminum.